docs: def getSpatialAnchorDescriptor(self, unHandle, pchDescriptorOut):
          """
          Get the descriptor for a given handle.  This will be empty for handles where the driver has not
          yet built a descriptor.  It will be the application-supplied descriptor for previously saved anchors
          that the application is requesting poses for.  If the driver has called UpdateSpatialAnchorDescriptor()
          already in this session, it will be the descriptor provided by the driver.
          Returns true if the descriptor fits into the buffer, else false.  Buffer size should be at least
          k_unMaxSpatialAnchorDescriptorSize.
          """
  
          fn = self.function_table.getSpatialAnchorDescriptor
          punDescriptorBufferLenInOut = c_uint32()
          result = fn(unHandle, pchDescriptorOut, byref(punDescriptorBufferLenInOut))
          return result, punDescriptorBufferLenInOut.value